The invention relates to a bicycle trailer and, in particular, to a bicycle trailer hitch for connecting a bicycle trailer to a bicycle.
Bicycle trailers have become quite popular for carrying children and cargo. The bicycle trailers are hitched to the rear of the bicycle and towed therebehind.
Most previous hitches are connectable to the chain stay or to both the chain stay and the seat stay of the bicycle to retain the hitch arm of the trailer. These hitches can be difficult to secure and sometimes require precise adjustment for proper operation. In addition, the hitches are not useful with some new bicycle designs having modified frame connection to the rear wheel.
Recently hitches have been introduced that secure into the rear axle of the bicycle. One such hitch is described in U.S. Pat. No. 6,099,008 to Caffey. The axle-mounted hitches can work with quick disconnects and are easy to connect to the bicycle. However, they include complex arrangements for connection to the hitch. In particular, the connection arrangements include pins that are passed through alignable apertures in the hitch arm and in the bracket that is attached to the bicycle. This procedure is often frustrating, as the trailer can be difficult to maneuver when grasping the end of the hitch arm.
In addition, the previous axle-mounted hitches include complex universal joint arrangements including many interconnected parts and bearings. This increases the cost of the hitch to consumers. Since many axle-mounted hitches are purchased to replace an existing hitch that no longer works with a new bicycle design, it is particularly desirable to provide a replacement hitch that is as inexpensive as possible, while providing excellent performance.
A bicycle trailer hitch according to the present invention connects to the rear axle of a bicycle and is not clamped to the chain or seat stays. The hitch securely and effectively hitches a trailer to a bicycle, but is simple to install and use. The hitch is also economical to manufacture and therefore can be offered to consumers at low price.
In accordance with a broad aspect of the present invention, there is provided a bicycle trailer hitch for securing a trailer to a bicycle, the trailer including a hitch arm and the bicycle having a rear wheel including an axle with an axis of rotation and a frame, the bicycle trailer hitch comprising: a hitch ball including a connector end connectable to the trailer hitch arm and an opposite end formed as a ball; and a bicycle-mounted hitch portion including a plate having an aperture extending therethrough, the plate being mountable on the axle of the rear wheel of the bicycle with the axle extending through and rotatable within the aperture and a socket connected to the plate and formed to removably retain the ball of the hitch ball.
The hitch ball connector end is preferably formed to be releasably connected, as by pinning, to the hitch arm. In one embodiment, the connector end is an insert sized to fit into the hollow end of the hitch arm, which is formed of tubing. The connector end can alternately be a cup sized to fit over the outboard end of the hitch arm. A pin, threaded bolt, etc. can be pinned through the insert or cup and the hitch arm.
The connector end is preferably formed integral with the ball end. An intermediate portion extends between the ball end and the connector end. The intermediate portion is reduced in diameter relative to the ball end and extends out from the socket while the ball end is retained therein. Preferably, the intermediate portion is formed of a resilient material to permit some flexion between the connector end and the ball end.
The plate of the bicycle-mounted hitch portion is preferably mounted between an end of the axle and the frame of the bicycle to which the rear wheel is mounted. The plate is preferably restrained, as by tight clamping, from pivoting about the axle. Clamping can be provided by a quick release mechanism or by a fastener secured onto the axle. Preferably, the aperture extends through the plate such that, when the bicycle-mounted hitch portion is mounted to the axle, the plate extends substantially orthogonal to the axle axis of rotation and the socket is spaced from the aperture. This provides that the standard axle securing means, such as a fastener or quick release mechanism can be clamped against the plate without modifying the standard axle mounted arrangement of the bicycle.
The socket of the bicycle-mounted hitch portion is preferably formed integral with the plate. The socket can be formed to closely surround and correspond with the shape of the ball end of the hitch ball. Alternately, the socket can be formed to simply retain the ball end therein without consideration as to the shape of the ball head. Of course, when the socket is formed to closely surround and correspond with the shape of the ball end, this offers more even wear between the ball and the socket and more favourable transfer of forces within the hitch.
The socket includes an open end, sized to permit the ball end of the hitch ball to pass therethrough, and a retainer end. In one embodiment, the open end includes a closure mechanism, such as for example a removable pin, a releasable catch or a latchable gate, such that the open end can also act to retain the ball end in the socket. Where a pin is used, it is not inserted through the hitch ball, thereby avoiding the problems of having to align apertures between the hitch ball and the socket. In one embodiment, the open end is positioned at the forward end of the socket and the retainer end is positioned at the rear of the socket such that the ball end is retained in the retainer end when the hitch arm of the trailer is extending out from the hitch behind the bicycle. A slot is provided between the open end and the retainer end and sized to permit the intermediate portion of the hitch ball to slide therein while the ball is retained in the socket. Preferably the slot is positioned to open at a side of the socket facing away from the wheel of the bicycle.